If Central Park were a woman and had just one beau, he would be a hunched, shiny-scalped man named Isidore Block. When Isidore Block dies, which could be soon, a bereft Central Park will surely mourn his loss. Mr. Block, 82, is a man you probably saw. He shuffled around the park with a bell he’d ask you to ring. His shoes spliced open for comfort, pushing an old stroller, he made the park his salon. He reminded you of Ed Koch, with the same wispy white side-hairs, door-knocker nose and nasal yet soothing voice.